import path from 'path';

import { components } from '@octokit/openapi-types';

import { RepositoryHelper } from './repository';
import { getChangedLineNumbersFromPatch } from './parseGitPatch';

type PullRequest = components['schemas']['pull-request'];
type PullRequestFile = components['schemas']['diff-entry'];

export class PullRequestHelper extends RepositoryHelper {
  protected prNumber: number;

  protected prQuery: {
    owner: string;
    repo: string;
    pull_number: number;
  };

  protected prData: PullRequest | undefined;

  constructor(owner: string, repo: string, prNumber: number, octokit: unknown = undefined) {
    super(owner, repo, octokit);
    this.prNumber = prNumber;
    this.prQuery = {
      owner,
      repo,
      pull_number: prNumber,
    };
  }

  async getBranchName(): Promise<string> {
    return (await this.getPr()).head.ref;
  }

  async getTitle(): Promise<string> {
    return (await this.getPr()).title;
  }

  async getUrl(): Promise<string> {
    return (await this.getPr()).html_url;
  }

  async getReviewers(): Promise<string[]> {
    const requestedReviewers = (await this.getPr()).requested_reviewers?.map((r) => r.login);

    const reviewResponse = await this.getOctokit().rest.pulls.listReviews(this.prQuery);
    const actualReviewers = reviewResponse.data.map((r) => r.user?.login ?? '').filter((r) => r.length > 0);

    return [...(requestedReviewers ?? []), ...actualReviewers];
  }

  async getFiles(): Promise<PullRequestFile[]> {
    const prResponse = await this.getOctokit().rest.pulls.listFiles(this.prQuery);
    return prResponse.data;
  }

  async hasQualifiedChanges(fileExtensions: string[], linesChangedThreshold: number): Promise<boolean> {
    return (
      (await this.getFiles())
        .filter(
          (f) =>
            !['renamed', 'removed', 'unchanged'].includes(f.status) &&
            fileExtensions.includes(path.extname(f.filename).toLowerCase()),
        )
        .map((f) => getChangedLineNumbersFromPatch(f.patch as string).length)
        .reduce((partialSum, numLines) => partialSum + numLines, 0) > linesChangedThreshold
    );
  }

  async addComment(body: string): Promise<void> {
    await this.getOctokit().rest.issues.createComment({
      owner: this.owner,
      repo: this.repo,
      issue_number: this.prNumber,
      body,
    });
  }

  private async getPr(): Promise<PullRequest> {
    if (!this.prData) {
      const prInfoResponse = await this.getOctokit().rest.pulls.get(this.prQuery);
      if (prInfoResponse.status !== 200) {
        throw prInfoResponse;
      }
      this.prData = prInfoResponse.data;
    }
    return this.prData;
  }
}